Fuel injector for internal-combustion engines



Oct. 3, 1944.

A. G. PETERS FUEL INJECTOR FOR INTERNAL-COMBUSTION ENGINES Filed May 14, 1941 Patented Oct. 3, 1944 FUEL INJECTOR FOR INTERNAL-COMBUS- TION ENGINES Alyard G. Peters, Rockport, Wash., assignor to Peters Fuel Injection, Inc., Seattle, Wash., a corporation of Washington Application May 14, 1941, Serial N0. 393,408

3 Claims.

This invention relates to a fuel injector for internal combustion engines.

An object of this invention is to provide a fuel injector that is adapted to handle any kind of liquid fuel now used in internal combustion engines, including the lighter fuels such as gasoline, and that is adapted for use in connection with either the Diesel type or the ordinary gasoline burning type of internal combustion engines.

Another object is to provide a fuel injector that will im'ect the fuel at a substantially constant pressure irrespective of the speed of the engine and irrespective of the amount of fuel injected at each stroke.

Another object is to provide a fuel injector in which a spring is used as a source of power to inject the fuel thereby making possible a very quick injection of the fuel irrespective of the speed of the motor.

Another object is to provide a fuel injector that may be used for injecting gasoline and other light fuels into ordinary internal combustion en- -gines thereby making it possible to dispense with all high tension ignition mechanism and to use a glow plug type igniter that will operate on low voltage and further making it possible to dispense with the usual float carburetor which necessitates the maintenance of a supply of gasoline or like fuel in close proximity to the motor andl thus constitutes a fire hazard.

Other objects are to provide fuel injector means that will increase the horse power of an engine, save fuel, provide a higher efficiency and greater reliability and do away with the trouble incident to carburetion and high tension ignition devices.

Another object is to provide fuel injector means of simple and efficient construction that is easily accessible for the purpose of repair and replacement and in which a separate injector unit is provided for each cylinder of an engine so that if one injector unit becomes inoperative the remaining units may continue to function normally.

Fuel injectors now in common use are not adapted to use gasoline because the pump plungers of such fuel injectors are fitted so slosely in their cylinders that theyrequire lubrication to prevent them from seizing and binding in the cylinders. Some gasoline will pass even the pistons with the least clearance but this gasoline does not provide enough lubrication to prevent seizure. In accordance with my invention I proilxvidea greater amount of piston clearance than Tisordinarily provided to thereby eliminate dangr of` piston seizure and I further provide spring actuated means for driving the pump plunger at high speed on the injection stroke to thereby inject a. charge of fuel very quickly so that very little of the fuel charge will have time to leak back past the piston and so that the fuel will be very efdciently atomized as it enters the engine cylinders.

.Asv an example of piston clearances in fuel injector pumps I find that in many fuel injector pumps now in common use the pistons are tted to a clearance of two millionths of an inch, whereas, in my injector, clearances up to ten millionths of an inch are allowable.

Other objects of my invention will be apparent from the following description taken in connection with the accompanying drawing.

Figure 1 is a sectional view taken substantially on broken line I--I of Fig. 2, showing a fuel injector constructed in accordance with my invention, parts being shown in elevation and other parts being broken away.

Fig. 2 is a sectional view of the same taken substantially on broken line 2--2 of Fig. 1, parts being shown in elevation and parts being broken away.

Fig. 3 is a sectional view unaI larger scale than the preceding figures taken substantially on broken line 3-3 of Fig. 1.

Like reference numerals designate like parts throughout the several views.

In the drawing, 5 designates a housing of any suitable shape and size to meet the requirements of the engine with which it is connected.

A plurality of fuel injector units are provided in the housing 5. The number of injector units l provided 'in this housing 5 will correspond to the number of cylinders of the engine to which fuel is being supplied. Only one fuel injector unit is shown in the drawing.

Each fuel injector unit comprises a tubular pump housing 6 rigidly connected with the housing 5. A pump plunger 'I is operatively disposed within a bore 8 in the pump housing 6 and is connected with a larger plunger member 9 that is reciprocable within a chamber I0 in said pump housing B.

The plunger member 9 is connected by a rod II, links I2 and pivots I3 and I4 with a. lever member I5.

The lever I 5 is pivotally mounted on a shaft I6 that extends crosswise of the housing 6. The lever I5 has a shoulder I1 provided thereon for engagement with a cam I8 by which the amount of movement of said lever I5 is limited. The cam I8 is rigid with a shaft I9 which extends to the exterior of the housing 5 and is connected with a lever 28 and a link 2I which are used for positioning the cam I8. v

The lever I5 is urged in a. clockwise direction, as respects the showing in Fig. 1, by a relatively strong compression spring 22. The spring 22 may be disposed within a cup 23 that is secured to the housing 5. Preferably a bearing member 24 is provided in the end portion of the spring 22, said bearing member having a convex spherical surface 25 that is positioned within a suitable' spherical recess in a boss 28 on the lever I5 whereby a ball type bearing is provided between the spring 22 and lever I5.

The upper end portion of the lever I5 is provided With a shoulder 21 that is adapted to be engaged by the end portion of a pawl 28 to hold the lever I5 against the pressure .of the spring 22.

The pawl 28 is pivoted on pivot means 29. The pivot means 29 may be a shaft which extends lengthwise of the housing 5.

A cam shaft 38 extends lengthwise of the housing 8 and is journaled in bearings 3I in said housing. Two cams 32 and 33 are provided on the cam shaft 38 for operating the lever I5 and the pawl 28 respectively.

The cam 32 isadapted to engage with a roller 34 that is connected by a bearing member 35 with the lever I5. The cam 33 is adapted to engage with a roller 38 that is connected by a bearing member 31 with the pawl 28. f

The pawl 28 is urged toward the lever I5 by a compression spring 38.

The cam shaft 38 is connected by any suitable means, not shown, with the engine to which fuel is to be supplied, the cam shaft 38 being driven at the same speed as the engine shaft in the instance of a two cycle engine, and the cam shaft 38 being driven at half the speed of the engine shaft in the instance of a four cycle engine.

The structure of this fuel injector mechanism is particularly well adapted for the handling of light fuels, such as gasoline. The pump plunger 1 reciprocates in the fbore 8. Fuel enters the bore 8 under low pressure through a fuel inlet port 39 connected with a fuel inlet conduit 48. When the pump plunger 1 is retracted it is clear of the inlet port 39. When said pump plunger-is moved to discharge a jet of fuel it rst passes and closes off the inlet port 39 and then expels a, predetermined amount of fuel, depending on the length of stroke of said plunger.

'Ihe housing 8 is preferably connected by a nut 4I with a conduit 42. r'I'lie conduit 42 is preferably connected by a. nut 43 with a' fuel injector nozzle 44. The nozzle 44 is adapted to project into an engine cylinder 45 so as to de'- liver a spray oi' fuel thereinto. Preferably a separable nozzle tip 48 is threaded onto the nozzle 44.

The tip member 48 has a conical recess 41 in the outer end thereof within which a, conical nozzle valve 48 is adapted to seat. The nozzle valve 48 has a stem 49 that 'extends upwardly into the nozzle tip 44 and terminates in a chamber 52.

A compression spring 58- on the stem 49 bears against a nut 5I and yieldingly holds the conical valve 48 in engagement with the seat 41.

A plurality of liquid fuel passageways 53 are provided in the walls of the tip member 48 and intersect the conical valve seat 41 to provide for dischargingk fuel between the valve 48 and the seat 41. At their upper ends the passageways 53 communicate by an annular groove 54 and passageways 55 with a bore 58 in -the nozzle member 44.

It is to be noted that the valve 48 is positioned at the extreme end portion of the nozzle where said valve will be entirely within the engine cylinder, as contrasted to injector valves of this nature whcih are usually placed within recesses in the cylinder walls. This insures agood distribution of the fuel in the cylinder.

Also it will be noted that the pressure within the engine cylinder tends to holdthis 'valve closed as contrasted to the usual fuel injector valve of this nature which is arranged so that cylinder pressure tends to hold it open.

With my valve, fuel under pressure is forced out past the valve 48 against the fpressure of the spring 58 and against the cylinder pressure, whenever a charge is being injected into the cylinder. I'his keeps the fuel discharge passageway between the valve 48 and the wall of the recess 41 always clean and free from carbon due to the scouring action of the oil as it is forced out past the valve into the engine cylinder.

Also the stem 49 of my valve terminates in the chamber 52 and if there is any leakage of oil past this stem this oil can not reach the exterior of the fuel injector but will remain in the chamber 52 whereit will do no harm.

The valve 45 is of conical shape and the fuel will be sprayed into the cylinder in the form of a finely atomized hollow cone and will mix with the air very thoroughly and evenly.

'I'he operation of this device is as follows:

Fuel is supplied under low pressure through the fuel supply conduit 48 so that the passageways between the fuel supply conduit 48 and the valve -48 are always filled with fuel. The pump plunger 1 is driven downwardly by the spring 22 which always exerts the same force and always provides uniform operation in that it always sprays the charge in the same way.

The plunger 1 does not need to have an unusually close fit in the bore 8 to successfully handle light fuels such as gasoline. If some fuel does leak back past the plunger v1.this fuel will only return to the4 inlet 48 and the cam `I8 may f be moved to insure the delivery of the desired amount of fuel at each stroke.

The cam shalft 88 is connected with the shaft f of the engine to which fuel is being supplied and is rotated at the proper speed, i. e. at the same speed as the crank shaft for ya two cycle engine and at one half the speed of the crank shaft for a, four cycle engine.

As the cam shaft 88 rotates the cam 82,-by its engagement with roller 84, will move the lever I8 in a counterclockwise direction. as respects the showing in Fig. y1, thus compressing the spring 22, retracting the pump plunger 1 and allowing the pawl 28 to be moved into engagement with the shoulder 21 so as to momentarily hold the plunger 8 retracted and the spring 22 compressed.

As the cam shaft 88 continues to rotate the cam 32 will be retracted from the roller 84 and the cam 32 willengage with the miler 38 and lift the pawl 28 thus releasing the lever I5 and allowing the spring 22 to impart a quick downward stroke to the plunger 1. The spring 22 will always act with the same force and inject the fuel at the same speed irrespective of the speed of the engine. 'I'he length oi' stroke of the` plunger 1 will be determined by the setting of the cam Il thus providing a throttle means by which the speed of the engine may be controlled. l

The spring 22 moves the plunger 'l at relatively high speed on the fuel injection stroke. I have determined that the speed of this injection stroke is fast enoughto inject a charge of gasoline in lesstime than it will take this charge to be consumed by the explosion in the cylinder. When the plunger 1 isentirely retracted it is clear of the fuel inlet opening and when the spring 22 is first released and begins to move this plunger it will offer very little resistance to such y movement until after it has moved far enough to cover the fuel inlet opening. This allows the spring 22 to start its movement and pick up speed under a light load so that the plunger 1 will be moving at high speed before it starts to inject the fuel. This insures high speed fuel injection and efficient fuel atomization irrespective of the speed of the engine.

The use of this fuel injector makes it possible to operate an ordinary internal combustion engine at a higher compression ratio than is usu ally used. Also it makes possible successful ignition with a glow plug type igniter thereby making it possible to dispense with the usual high tension ignition system including the ignition coil timer and spark plugs.

The foregoing description and accompanying drawing clearly discloses a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that changes may be made in the invention within the scope and spirit of the following claims.

I claim:

1. In a fuel injector, an injector housing; a pump housing; a pump cylinder in said pump housing; fuel supply means connected with said pump cylinder; a pump plunger reciprocable in said pump cylinder and extending into said injector housing; a lever member fulcrumed in said injector housing; means connecting said pump plunger with said lever member for reciprocably moving said pump plunger by oscillation of said lever member; spring means adapted to move said lever and said plunger in a direction to discharge fuel from said pump cylinder; cam means adapted to retract said plunger and compress said spring means; lever member locking means adapted to lock said lever in a position in which said spring means is compressed and said pump plunger retracted; and means for releasing said lever locking means.

' 2. In 'a fuel injector, an injectorl housing; a` pump housing; a pump cylinder in said pump` housing; fuel supply means connected with said pump cylinder; a pump plunger reciprocable in I said pump cylinder and extending intosaid in'' V jector housing; a lever member fulcrumed in'l said injector housing; link means connecting said. f; pump plunger with said lever memberfor reciprocably moving said pump plunger Aby oscillation of said lever member; a compression;'spring'l adapted to move said lever .and -saidplunger on the fuel injection stroke'of the plunger; a cam adapted to retract said plunger and compressl said spring; xa pawl adapted to engage said lever to hold the same in a position with said spring compressed; another cam 'adapted to release said pawl; and operator controlled meansto limit the injection stroke of said plunger. y,

2. In a gasoline injector for internal combustion engines. a pump cylinder; anunobstructed 1' v s conduit free from check valves and like ob'stl'uc-L` v 4- erable in said pump cylinder and having an end portion movable back and forth over said' gasoline inlet port in the normal operationy of the plunger, whereby said plunger will move freely and at high speed on an injection stroke before it covers saidport and will impart a sharp blow to the column of gasoline in said conduit upon covering said port; spring means in said injector housing adapted to move said plunger at high speed on injection strokes thereof; cam means in said injector housing operable to place said spring means under stress and to retract said plunger after an injection stroke thereof; and spring releasing devices operable after`the operation of said cam means to provide instant and complete release of said spring means at the beginning of a fuelinjection stroke of said plunger.

, ALYARD G. PETERS. 

